Research on charged colloid propulsion summary report
Charged colloidal carbon particle produced and measured using cold cathode ion source, colloidal carbon feeding device, and electrode collector
COLLOID↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Tailoring Chemical Absorption-Precipitation to Lower the Regeneration Energy of a CO 2 Capture Solvent
Solvent-based CO 2 capture consumes significant amounts of energy for solvent regeneration. To improve energy efficiency, this study investigates CO 2 fixation in a solid form through solvation, followed by ionic self-assembly-aided precipitation. Based on the hypothesis that CO 3 2- ions may bind with monovalent metal ions, we introduced Na + into an aqueous hexane-1,6-diamine solution where CO 2 forms carbamate and bicarbonate. Then, Na + ions in the solvent act as a seed for ionic self-assembly with diamine carbamate to form an intermediate ionic complex. The recurring chemical reactions lead to the formation of an ionic solid from a mixture of organic carbamate/carbonate and inorganic sodium bicarbonate (NaHCO 3 ), which can be easily removed from the aqueous solvent through sedimentation or centrifugation and heated to release the captured CO 2 . Mild-temperature heating of the solids at 80–150 °C causes decomposition of the solid CO 2 -diamine-Na molecular aggregates and discharge of CO 2 . This sorbent regeneration process requires 6.5–8.6 GJ/t CO 2 . It was also found that the organic carbamate/carbonate solid, without NaHCO 3 , contains a significant amount of CO 2 , up to 6.2 mmol CO 2 /g-sorbent, requiring as low as 2.9–5.8 GJ/t CO 2 . In conclusion, molecular dynamic simulations support the hypothesis of using Na + to form relatively less stable, yet sufficiently solid, complexes for the least energy-intensive recovery of diamine solvents compared to bivalent carbonate–forming ions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Functionalized Silicon Particles for Enhanced Half- and Full-Cell Cycling of Si-Based Li-Ion Batteries
Vinylene carbonate (VC) and polyethylene oxide (PEO) have been investigated as functional agents that mimic the solid electrolyte interphase (SEI) chemistry of silicon (Si). VC and PEO are known to contribute to the stability of Si-based lithium-ion batteries as an electrolyte additive and as a SEI component, respectively. In this work, covalent surface functionalization was achieved via a facile route, which involves ball-milling the Si particles with sacrificial VC and PEO. Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy indicate that the additives are strongly bound to Si. In particular, MAS NMR shows Si–R or Si–O–R groups, which confirm functionalization of the Si after milling in VC or PEO. Particle size analysis by dynamic light scattering reveals that the additives facilitate particle size reduction and that the functionalized particles result in more stable dispersions based on zeta potential measurements. Raman mapping of the electrodes fabricated from the VC and PEO-coated active material with a polyacrylic acid (PAA) binder reveals a more homogenous distribution of Si and the carbon conductive additive compared to the electrodes prepared from the neat Si. Furthermore, the VC-milled Si strikingly exhibited the highest capacity in both half- and full-cell configurations, with more than 200 mAh g –1 measured capacity compared to the neat Si in the half-cell format. This is linked to an improved electrode processing based on the Raman and zeta potential measurements as well as a thinner SEI (with more organic components for the functionalized Si relative to the neat Si) based on XPS analysis of the cycled electrodes. In conclusion, the effect of binder was also investigated by comparing PAA with P84 (polyimide type), where an increased capacity is observed in the latter case.
25 ENERGY STORAGE↗
Trace Adsorptive Removal of PFAS from Water by Optimizing the UiO‐66 MOF Interface
Abstract The confluence of pervasiveness, bioaccumulation, and toxicity in freshwater contaminants presents an environmental threat second to none. Exemplifying this trifecta, per‐ and polyfluoroalkyl substances (PFAS) present an alarming hazard among the emerging contaminants. State‐of‐the‐art PFAS adsorbents used in drinking water treatment, namely, activated carbons and ion‐exchange resins, are handicapped by low adsorption capacity, competitive adsorption, and/or slow kinetics. To overcome these shortcomings, metal–organic frameworks (MOFs) with tailored pore size, surface, and pore chemistry are promising alternatives. Thanks to the compositional modularity of MOFs and polymer–MOF composites, herein we report on a series of water‐stable zirconium carboxylate MOFs and their low‐cost polymer‐grafted composites as C 8 –PFAS adsorbents with benchmark kinetics and “parts per billion” removal efficiencies. Bespoke insights into the structure–function relationships of PFAS adsorbents are obtained by leveraging interfacial design principles on solid sorbents, creating a synergy between the extrinsic particle surfaces and intrinsic molecular building blocks.
Ilić, Nebojša↗
Electrochemical reduction of per- and polyfluorinated alkyl substances (PFAS): is it possible? Applying experimental and quantum mechanical insights from the reductive defluorination literature
Remediation of per- and polyfluorinated alkyl substances (PFAS) in global water systems is a critical human and environmental health challenge facing society. PFAS consumption is associated with a litany of adverse health effects, and our knowledge of these dangers is still evolving. Current techniques to remove PFAS from water include adsorption to media (e.g. granular activated carbon, ion-exchange resin), nanofiltration, and reverse osmosis. However, these processes create a concentrated PFAS residual that requires further management. Destructive techniques are therefore needed to detoxify these residuals. Oxidative techniques have garnered the most attention (e.g. supercritical water oxidation, electrochemical oxidation) but are energy intensive and potentially form toxic by-products. As an alternative, several groups have researched advanced reduction processes that form aqueous electrons, but these processes are still chemical and energy intensive (e.g. ultraviolet/SO 3 2− , electron beam). This concise review therefore focuses on whether electrochemical reduction — a chemical-free, modular process — could be technically feasible for PFAS destruction.
King, Jacob F.↗
Restoring Escaped Zincate in Rechargeable Alkaline Zinc Batteries with a Seed-in-Nanoshell Design
Rechargeable alkaline zinc batteries are promising candidates for safe and low-cost energy storage, but suffer from ZnO dissolution that causes irreversible active material loss and rapid capacity decay. Here, we report a seed-in-nanoshell ZnO anode architecture that mitigates dissolution by combining physical confinement with electrochemical restoration of dissolved zincate species. ZnO particles are encapsulated within an ion-sieving carbon nanoshell that restricts zincate diffusion, maintains electrical conductivity, and stabilizes repeated solid–solution–solid transformations. Silver (Ag) nanoparticles incorporated into the nanoshell act as zincophilic nucleation seeds, lowering the Zn deposition barrier and directing the redeposition of dissolved zincate back to metallic Zn during charging. This confinement-enabled restoration mechanism converts zincate dissolution from an irreversible loss pathway into a recoverable process, enabling improved performance under harsh test conditions. The anode also delivers 227.9 mAh g −1 at −40 °C. Finally, a scalable tens-of-gram synthesis of ZnO@Ag is demonstrated, underscoring the practical potential of this strategy for advanced aqueous zinc batteries.
25 ENERGY STORAGE↗
Bayesian Model for HOPE Mass Spectrometers on Van Allen Probes
Space instruments rely heavily on modeling to predict and understand the instrument response, enabling a determination of the capabilities and resolution. The Bayesian approach provides a framework to incorporate prior knowledge and propagate uncertainty to predict the instrument response. We present an empirical Bayes model for the end-to-end performance of the Helium, Oxygen, Proton, and Electron mass spectrometers aboard the Van Allen Probes mission. In this model, we use a combination of external modeling, laboratory calibration, and expert opinion to construct the time-of-flight spectra and demonstrate good agreement with on-orbit data. The empirical Bayes model is applied to explore doubly charged ions and carbon, nitrogen, oxygen discrimination during the Van Allen Probes mission.
47 OTHER INSTRUMENTATION↗
Addressing Limitations of the Endpoint Slippage Analysis
Some rate of oxidation and reduction side-reactions will inevitably coexist in most rechargeable batteries. While parasitic reduction traps electrons, parasitic oxidation donates electrons to the cell’s inventory and may cause temporary capacity gain. Consequently, capacity measurements can provide unreliable information about the total extent of side-reactions occurring in the cell. The most widely used method to determine the rate of both these parasitic processes involves analyzing the slippage of endpoints, which consists in tracking the termination of cell charge and discharge when data is represented along a cumulative capacity axis. Here, we argue that this approach could lead to inaccuracies when applied to certain systems, which includes Si electrodes in Li-ion batteries and hard carbon in Na-ion batteries. This inaccuracy originates from the smooth nature of the voltage profiles of these materials at low and high alkali-ion content, causing the termination of charge and discharge to be dictated by voltage changes at both the positive and negative electrodes. We analyze this issue in quantitative terms and propose equations that can provide true rates of parasitic processes from experimental endpoint slippage data. This work shows that, in battery science, well-established analytical approaches may not be directly transferrable to new electrode systems.
25 ENERGY STORAGE↗
Use of carbon electrodes to reduce mobile ion concentration and improve reliability of metal halide perovskite photovoltaics
Ion migration is one of the prime reasons for the rapid degradation of metal halide perovskite solar cells (PSCs), and we report on a method for quantifying mobile ion concentration (No) using a transient dark current measurement. We perform both ex-situ and in-situ measurements on PSCs and study the evolution of No in films and devices under a range of temperatures. We also study the effect of device architecture, top electrode chemistry, and metal halide perovskite composition and dimensionality on No. Two-dimensional perovskites are shown to reduce the ion concentration along with inert C electrodes that do not react with halides by ~99% while also improving mechanical reliability by ~250%. We believe this work can provide design guidelines for the development of stable PSCs through the lens of minimizing mobile ions and their evolution over time under operational conditions.
14 SOLAR ENERGY↗
ION Validation of Transformational CO2 Capture Solvent Technology with Revolutionary Stability: “Project Apollo”
This final report presents all the work and tests performed during ION’s carbon dioxide (CO2) capture pilot test campaign at the 0.6 MWe scale in the Pilot Solvent Test Unit (PSTU) at the National Carbon Capture Center (NCCC): “Validation of Transformational CO2 Capture Solvent Technology with Revolutionary Stability,” referred to as the “Apollo” Project (DE-FE0031727).
Meuleman, Erik↗
Lignite-Derived Carbon Materials for Lithium-Ion Battery Anodes
Oral Presentation on the Project Progress
Hou, Xiaodong↗
Lignite-Derived Carbon Materials for Lithium-Ion Battery Anodes
Oral Presentation on the Project Progress
Hou, Xiaodong↗
PFAS Waste Management for Industrial, Water, and Wastewater Treatment Facilities
Per- and polyfluoroalkyl substances (PFAS), including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are widely used in industrial and consumer products due to their unique water and oil repelling properties. These slow-degrading and bio-accumulating compounds, often called "forever chemicals," are not typically removed by conventional industrial and municipal water/wastewater (W/WW) treatment. This tip of the month provides comprehensive strategies for managing PFAS-contaminated waste streams. Understanding the various types of PFAS waste streams is the first step in managing them. Primary PFAS waste includes contaminated process W/WW and solid materials directly from the production and processing of PFAS-containing materials. These might come from manufacturing facilities, firefighting training areas, or other industrial operations where PFAS compounds are used or were historically present. Secondary PFAS waste results from treatment and disposal mechanisms of primary PFAS waste streams, including spent activated carbon, used ion exchange resins, membrane reject streams, PFAS-laden backwash water, landfill leachate, incineration residuals, etc. TABLE 1 lists examples of the most common PFAS waste streams in different industrial facilities.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
INTERACTION ENERGIES FROM SCATTERING CROSS SECTIONS OF HYDROGEN IONS IN CH SUB 4, CF SUB 4, C SUB 2 H SUB 6, AND C SUB 2 F SUB 6
Interaction energies from scattering cross section of hydrogen ions in methane, carbon tetrafluoride, ethane, and hexafluoroethane
METHANE↗